Iapetus is a world of sharp contrasts. The leading hemisphere is as dark as a freshly-tarred street, and the white, trailing hemisphere resembles freshly-fallen snow.

Friday's flyby was the first close encounter of Iapetus during the four-year Cassini tour. The second and final close flyby of Iapetus is scheduled for 2007.

Next up for Cassini is communications support for the European Space Agency's Huygens probe during its descent to Titan on Jan. 14.

The Huygens probe successfully detached from the Cassini orbiter on Dec. 24. The data gathered during the descent through Titan's atmosphere will be transmitted from the probe to the Cassini orbiter.

Afterward, Cassini will point its antenna to Earth and relay the data through NASA's Deep Space Network to NASA's Jet Propulsion Laboratory, Pasadena, Calif., and on to the European Space Agency's Space Operations Center in Darmstadt, Germany, which serves as the operations center for the Huygens probe mission.

Two of the instruments on the probe -- the camera system and the gas chromatograph/mass spectrometer -- were provided by NASA.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Science Mission Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter.

The European Space Agency built and managed the development of the Huygens probe and is in charge of the probe operations. The Italian Space Agency provided the high-gain antenna, much of the radio system and elements of several of Cassini's science instruments.